The kinematics equations of robotic manipulator is derived according to moving frame system
method in this study; volume element is defined employing exterior differential and moving frame system and
is taken as kinematics performance index measuring redundant robotic manipulatorís manipulability. Then take
the 7-DOF automatic fiber placement robotic manipulator as an example and obtain the volume element
function of it. Compared the volume element function which derived with Yoshikawa's manipulability function,
it shows the volume element function and the manipulability function are the same, so the volume element as
a kinematics performance index is feasible.